Brown ground beef and salt generously (with kosher salt) and pepper in a large skillet over medium heat.
Add 1/4 cup chopped onion and 1 cup tomatoes. Cook until meat is thoroughly cooked, stirring occasionally. Drain mixture.
In the meantime, chop the potato into 1-inch cubes—Fry in a skillet, seasoning with seasoned salt, until tender and crusty. Allow potatoes to drain on paper towels. After draining, pour the meat mixture into a bowl and add 1 cup of shredded cheese, ketchup and mustard. Add another tablespoon or so of chopped onion and another 1/4-1/2 cup fresh tomatoes. Taste and add a little seasoned salt if necessary.
Return the meat mixture to the stove and add a few tablespoons of water. Simmer for about 10 minutes, stirring occasionally. Add potatoes and simmer for 5-10 more minutes. Spoon into bowls, add a little shredded cheese, tomatoes and onion. A couple of sunny-side-up eggs might not hurt either!